Production of cyclic organosilicon compounds



Patented Jan. 5, 1954 PRODUCTION OF CYCLIC ORGAN OSILIGON COMPOUNDSDavid B. Hatcher, Evanston, Ill.,

assignor, by

mesne assignments, to Allied Chemical & Dye Corporation, New York, N.Y., a corporation of New York N Drawing. Original application August 9,1948, Serial No. 43,353. Divided and this application April 1, 1952,Serial No. 279,947

Claims. (Cl. 260-4482) The invention relates to the production of novelalicyclic organosilicon compounds whose molecule includes from one totwo silicon atoms attached to nuclear carbon atoms.

The principal object of the invention is the production of novelalicyclic silanes whose molecule includes from one to two silicon atomsattached to nuclear carbon atoms, the silanes being obtainable incomparatively large yields from readily available and inexpensivestarting materials. More specific objects and advantages are apparentfrom the following description, which illustrates and discloses but isnot intended to limit the scope of the invention.

United States Patent No. 2,258,218 discloses the production of curableorganosilicon compositions by the hydrolysis of a mixture ofmethyltrichlorosilane, dimethyldichlorosilane and trimethylchlorosilane.Cohydrolysis, with such a mixture of methylchlorosilanes, of a silaneembodying the invention results in substantially improved hydrolysis andcondensation products.

The silanes embodying the invention include those having the generalformula wherein each of the radicals X, X, X", Y, Y and Y" is ahydrolyzable radical. The two central pentavalent radicals are joined attwo points so that the radical in brackets is a radical derived fromdicyclopentadiene having an overall total of four free valences. Thus,the radical in brackets in the structural formula may have any ofseveral structures, e. g.,

Such a silane consists of a cycloalkane in the molecule of which twohydrogen atoms have been replaced by silicon atoms, each silicon atombeing attached to three hydrolyzable radicals in addition to a carbonatom in the molecule. One of the silicon atoms is attached to onenuclear carbon atom and the other is attached to a second nuclear carbonatom. Preferred silanes of the invention are those in which thehydrolyzable radicals are halo, most desirably chloro. Silanes embodyingthe invention include those having the general formula wherein R is adivalent alicyclic radical having 10 carbon atoms disposed in 3 rings,and each of the radicals X, X, X, Y, Y and Y" is a hydrolyzable radicalof the class consisting of halo, alkoxy, amino, aroxy and acyloxyradicals.

The free valences of the radical R are attached to different nuclearcarbon atoms. R may be adivalent radical which can be considered to bederived (by the removal of two hydrogens) fromoctahydro-4,7-methanoindene. Such silanes, having hydrolyzable haloradicals, are produced by the reaction of the invention, which alsoproduces trihalosilyl-heXahydro-4,7-methanoindenes.

Hydrolyzable radical is used herein to include halo, alkoxy, amino,aroxy and acyloXy. The halo radical is any one having an atomic weightless than (i. e., fluoro, chloro or bromo). The alkoxy radical is anyprimary or secondary alkoxy radical having from one to four carbon atoms(1. e., methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, isobutoxy orsecondary butoxy). Amino is simply the -NH@. group. Aroxy radicals areany in which the aryl group is phenyl, or a mono-, dior tri-substitutedphenyl radical, each substituent being a primary, secondary or tertiaryalkyl radical hav ing from one to five carbon atoms, the total number ofcarbon atoms in the side chains being not more than five (i. e., thearyl radical is phenyl, or ortho-, metaor para-methyl phenyl, any diortri-methyl phenyl, or any substituted phenyl in which the substituentsare: one ethyl; one ethyl and one methyl; two ethyls; two methyls andone ethyl; two ethyls and one methyl; either propyl radical; eitherpropyl radical and methyl; either propyl radical and two methyls; eitherpropyl radical and ethyl; any butyl radical; any butyl radical andmethyl; or any pentyl radical). The acyloxy radical has the generalformula in which E is a'saturated or unsaturated straight, branched orclosed chain hydrocarbon radical having from one to eighteen carbonatoms, or phenyl or substituted phenyl, the substituents, if any,consisting of from one to three alkylradicals each having from one tolive carbon atoms, and all having a total of not more than five carbonatoms, as hereinbefore described. The hydrolyzable radicals may be thesame or different. The preferred hydrolyzable radical is a halo radical,the most desirable being chloro.

silanes of the invention may be produced by means of a reaction betweendicyclopentadiene and a silicohaloforin, preferably silicochloroform.Dicyclopentadiene can be represented by any of several structuralformulas; the formula now most generally recognized is:

The silicohaloform can be silicofluoroform, silicochloroform orsilicobromoform. Silicoiodoform is too expensive to be of commercialsignificance. It is beli ved that two reactions proceed concurrently,one of which forms bis trihalosilyl octahydro lfi-methanoindenes, andthe other of which forms bis(trihalosilyl)cyclopentanes. The formationof bis(trihalosilyl)octahydro 4,7 methanoindenes is thought to indicatethat one reaction which proceeds in the practice of the invention is theaddition of the silicohaloform to the double bonds of thedicyclopentadiene. The formation of bis(trihalosilyl) cyclopentanes isthought to indicate that, under the conditions at which the reaction isconducted, some of the dicyclopentadiene dissociates to formcyclopentadione, to the double bonds of which the silicohalo form thenadds.

Thus, the practice of the invention results in the production, fromdicyclopentadiene and a silicohaloform, ofbis(trihalosilyl)octahydro-4,'7- methanoindenes andbis(trihalosily1)cyclopentanes. In addition, the practice of theinvention results in the production of material which is recovered as anintermediate distillation fraction (1. e., as a fraction having aboiling range intermediate between the boiling temperatures of thebis(trihalosi1yl)octahydro 4,7 methanoindenes and thebis(trihalosily1)cyclopentanes), which is thought to comprisetrihalosilylhexahydro 11,7- methanoindenes. Trihalosilylcyclopentenesmay also be obtained. Each of these products of the reaction ofdicyclopentadiene and a silicohaloform is an addition product of onemolecule of cyclopentadiene or dicyclopentadiene and from one to twomolecules of a silicohaloform.

The reaction which produces silanes of the invention (i. e., between asilicohaloform and dicyclopentadiene) proceeds readily at elevatedtemperature and pressure. The reaction is conducted either as a batchprocess (i e., in a bomb) or as a continuous process (i. e., byconducting the dicyclopentadiene and the silicohaloform into a reactionzone; removing the product, from the. re.- action zone; and separatingthe reactants from the silane products) the continuous process being thepreferred embodiment of the invention. The silane products from thereaction are separated by fractional distillation.

When the reaction is'conducte'd as a batch operation the silicohaloformand the dicyclopentadiene are introduced at room temperature into asteel high pressure bomb. The bomb is sealed, placed in a heatingjacket, and heated at a reasonably rapid rate to reaction temperature.(Usually the heating is eifected by a constant energy input so that theheating rate is rapid initially and gradually decreases until a maximumtemperature is attained. A constant heating rate may be employed ifdesired, but close temperature control is not essential when thereaction is conducted batchwise.)

It is believed that the reaction which produces the silanes of theinvention takes place slowly at temperatures as low as about 175 C. Itis known that the rate of reaction increases with increases intemperature, and it is usually preferable, therefore, to conduct thereaction at a temperature materially above room temperature. silanes ofthe invention are produced in substantial yields and in a reasonabletime when the reaction temperature is as low as about 275 C., althoughit is usually preferable to conduct the reaction at a temperature of atleast about 300 C. It is ordinarily advantageous that the bomb be heatedat a comparatively rapid rate to the reaction temperature, a heatingrate such that the temperature of the reactants is about 300 C. in fromabout 60 to about minutes after heating is started is usuallysatisfactory. Somewhat faster heating rates may be practical, but thelarge mass of metal in the bomb ordinarily heats rather slowly. It isusually desirable that slower heating rates be avoided. It is ordinarilyadvisable not to heat the bomb above about 400 C., and preferable not toheat the bomb above about 375 C. Apparently, higher temperatures do notaifect the products or the yield to a substantial extent, but theexpenditure of extra energy required to conduct the reaction at a highertemperature is not warranted. For the same reason, it is usually mostdesirable that the reaction be conducted at a temperature not higherthan about 350 C.

Because the reactants are gases at the reaction temperatures, it isusually desirable to conduct the reaction at superatmospheric pressureso that reasonable amounts of silanes of the invention can be preparedwithout the use of unduly large equipment. It has been found to bepractical to conduct the reaction at a pressure as low, as about 300pounds per square inch gauge, but it is usually preferable to use apressure of at least about 500 pounds per square inch gauge. Mostdesirably, the reaction is conducted at a pressure of at least about 700pounds per square inch gauge. In some instances it may be desirable toconduct the reaction at a pressure as high as about 1500 pounds persquare inch gauge, although it is usually preferable to use a pressurenot higher than about 1200 pounds per square inch gauge. Most desirablythe reaction is conducted at a pressure not greater than about 900pounds per square inch gauge.

It is desirable in all instances to avoid the introduction of air,containing moisture, which hydrolyzes the silanes in the reactor toproduce a hydrohalic acid.

It is believed that one reaction that occurs is between two molecules ofthe silicohaloform and one molecule of the alicyclic diene (i. e., thatthe ratio of the reactants participating in the reaction is two mols ofthe silicohaloform per mol of the dicyclopentadiene). The reaction whichis believed to occur is represented in Equation 1, below H 30/ con H CH21 ll +2(HSiCl3) HO I c on o o H Ha H /C\H ClaSiHC I o--onsict I CH2 1E20 C CH2 \O/H\C/ which shows the reaction of two molecules ofsilicochloroiorm with one molecule of dicyclopentadiene (i e., 3a, 4, 7,la-tetrahydro-fi-methanoindene) to produce one molecule or" 1,6-bis-(trichlorosilyl)octahydro i, methanoindene. It is known that thereaction produces bis(tri-- chlorosilyl) octahydro-4,'Zmethanoindenes,and it is believed that a mixture is produced which includes thel,6-bis(trichlorosilyl) octahydro-dflmethanoindene shown, as well as the1,5-, the 2,6- and the 2,5-compounds.

In some instances it may be desirable to use slightly less than thetheoretical proportions of the silicohaloform with thedicyclopentadiene, but it is usually desirable to use at least about 1mol of the sillcohaloform per mol of the dicyclopentadiene andpreferable to use at least about 2 mols per mol of thedicyclopentadiene. As has been stated herein, the production of somebis(trichlorosilyl) cyclopentane indicates that the dicyclopentadieneexists, in part, as cyclopentadiene under the conditions of thereaction; the theoretical amount of the silicohaloform required dependsupon the amount of the cyclopentadiene present in the reactor, and isnot determined solely on the basis of the dicyclopentadiene charged. Itis ordinarily most desirable to use at least about 4 mols of thesilicohaloform per mol of the dicyclopentadiene. Usually it is desirableto use not more than about 8 mols of the silicohaloforin per mol of thedicyclopentadiene, although much higher ratios can be used. Ordinarily,it is most desirable to use not more than about 5 mole of thesilicohaloforrn per mol of the dicyclopentadiene.

When a continuous reaction is used to produce silence of the invention,the temperature of the reaction zone should be controlled so that reaction occurs to the desired extent in the time during which the reactantsare present in the reaction zone. Thus the temperature of the reactionzone and the contact time that is used. are, in general, interdependent;with a shorter contact time the reaction temperature should be higher.The same considerations that govern the operating temperature rangeswhen the reaction is conducted batch-wise govern the temperature rangeswhen the reaction is run continuously.

It is usually desirable to preheat the reactants so that they areintroduced into the reaction zone at approximately the reactiontemperature. By this procedure the material entering the reaction zoneis already at reaction temperature, and it is only necessary to maintainthat temperature. In this way the reaction zone is kept to a minimumsize.

As noted above, the contact time that is used depends upon the operatingtemperature. Usually, it is desirable to use contact times not shorterthan about 10 minutes, and preferably to 4,7-methanoindene use contacttimes not shorter than about 15 minutes. Ordinarily, it is mostdesirable to use contact times not shorter than about 29 minutes.Usually, it is desirable to use contact times not longer than about 100minutes, and preferably to use contact times not longer than about 90minutes. Most desirably, contact times not longer than about minutes areused.

The same considerations that govern the proportions of reactants and thepressure used when the reaction is conducted as a batch operation governthe proportions of reactants and the pressure used when the reaction isconducted as a continuous operation.

Such reaction produces only cycloaliphatic compounds with trihalosilylsubstituents; these naterials can be subjected to further reactions toproduce cycloaliphatic compounds with silyl substituents other thantrihalosilyl. Ehus, alicyclic compounds with silyl substituents having,attached to the silicon atoms, one or more amino radicals are producedby reaction between ammonia and a bis(trihalosilyl)cyclopentane, atrihalosilylcyclopentene, a trihalosilylhexahydro or a bis trihalosilyloctahydro-4,7-methanoindene.

Cycloaliphatic compounds with silyl substituents having, attached to thesilicon atoms, allioxy radicals are produced by reaction between thebis(trihalosilyl) cyclopentane, trihalosilylcyclopentene,trihalosilylhexahydro4,7-methanoindene orbis(trihalosilyl)octahydrolJ-methanoindene and alcohols having thegeneral formula S-OH in which S is methyl, ethyl, propyl, isopropyl,n-butyl, isobutyl or secondary butyi. Alkoxy is substituted for halo bymeans of such a reaction, with corresponding formation of a hydrogenhalide.

Cycloaliphatic compounds with silyl substituents having, attached to thesilicon atoms, hydrolyzable acyloxy groups are produced by reactionbetween an acid anhydride and the silanes having hydrolyzable radicalswhich consist of alkoxy groups, or, in some instances, by reactionbetween the bis(trihalosilyl) cyclopentane, trihalosilylcyclopentene,trihalosilylhexahydro-41?- methanoindene orbis(trihalosilyl)octahydrolflnietihanoindene and the sodium salt of theorganic aci Alicyclic compounds with silyl substituents havinghydrolyzable aroxy radicals attached to the silicon atoms are preparedby reaction between the bis(trihalosilyl)cyclopentane,trihalosilylcyclopentene, trihalosilylhexahydro 4 7 methanoindene orbis(trihalosilyl) octahydro-4,"- methanoindene and phenol or monoallryb,dialkylor trialkyl-substituted phenols in which each alkyl substituenthas from one to live carbon atoms, and all the alkyl substituentscontain a total of not more than five carbon atoms, as hereinbef oredescribed.

Example Dicyclopentadiene is reacted with a silicohaloform according tothe following procedure:

silicoohloroform (271 grams) and dicyclopentadiene (132 grams) arecharged into a steel high pressure bomb having a capacity of about 1100ml. and the bomb is sealed, placed in a heating jacket, and heated,using a constant energy input suificient to achieve a temperature ofabout 290 C. (when the pressure is about 435 pounds per square inchgauge) approximately 70 minutes after heating is started, and atemperature of about 344 C. approximately minutes after heating isstarted. The temperature inside the bomb is maintained between about 310C. and about 340 C. for an additional 120 minutes, after which timeheating is discontinued; the bomb is allowed to cool; and the product(which is believed to contain trichlorosilylcyclopentenes, the -2 andthe -3 compounds) is removed from the bomb and separated by fractionaldistillation through a jacketed column 36 inches in length and 25 mm. indiameter, packed with glass helices. Mixtures ofbis(trichlorosilyl)-cyclopentanes (52 grams believed to be a mixtureofthe 1,2- and the 13- compounds; boiling range from 169 C. to 175 C. atan absolute pressure equal to about 55 mm. of mercury),bis(trichlorosilyl)octahydro- 4,7-methanoindenes (55 grams believed tobe a mixture of the 1,5-, the l,6-, the 2,5- and the 2,6- compounds;boiling range from 260 C. to 295 C.

at an absolute pressure equal to about mm. of

mercury) and an intermediate cut (33 grams believed to be a mixture oftrichlorosilylhexahydro- 4,7-methanoindenes, i. e., the 1-trichlorosilyl-, 2-trichlorosilyl-, and 5-trichlorosilylhexahydro-4,7-methanoindenes; boiling range from 178 C. to 206 C. at an absolutepressure equal to about 4 mm. of mercury) are recovered from thereaction products.

Results substantially the same as those described above may be obtainedby carrying out a reaction between dicyclopentadiene andsilicofiuoroform or silicobromoform, or a mixture of silicohaloforms.

This is a division of application Serial No. 43,353, filed August 9,1948, and now abandoned.

Having described the invention, I claim:

1. An organosilicon compound having the general formula wherein each ofthe radicals X, X, X, Y, Y and Y" is a radical of the class consistingof halo, alkoxy, amino, aroxy and acyloxy radicals and -R, is a divalentradical derived from octahydro-4,'7-methanoindene by removal of twohydrogen atoms from positions of the class consisting of the 1,6; 1,5;2,6 and 2,5 positions.

2. A bis(trihalosily1)octahydro-4,7 -methanoindene of the classconsisting of the 1,6; 1,5; 2,6

and 2,5 isomers.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,524,529 Krieble Oct. 3, 1950

1. AN ORGANOSILICON COMPOUND HAVING THE GENERAL FORMULA